PARASITOLOGY. 153 



Animals Infested.—ThQOTL, sheep, and goat. 



Parts Infested. — The colon and 

 ^^ (c^ caecum. 



Condition Produced. — The em- 

 bryos, upon being" taken into the 

 digestive tract of the host, have 

 been observed to reach maturity 

 in two to three weeks ; they hold 

 TrTchocephalusAffin.s firmly to the mucous membrane 

 Sheep and suck blood ; only a few have 



2 M^Te^^^ ^^^^ noted in infested animals 



a, Cephalic extremity, and uo serious rcsults have been 



b, Caudal extremity. ^^^^^^^^ -^^ ^his COUUtry. 



Trichocephalus Crenatus (Crena— notch). 



Sy7io7iyms.—VJh\p y^orm] Trichocephalus Dispar. 



Distribution. — Occasionally found in the United 

 States. 



Description.— In shape and appearance the male and 

 female resemble the Trichocephalus Ai^nis of sheep ; 

 the male measures one to one and one-quarter inches 

 long, the female one and one-half inches. 



Animals I^ifested.—The pig. 



Parts htfested.—The small intestines. 



Conditions Produced. — They are found firmly 

 attached to the mucous membrane. When only a 

 few are present no serious results occur ; when myr- 

 iads are present they cause diarrhoea, indigestion and 

 an unthrifty condition. 



Trichina Spiralis (Trix— hair; spira— coil). 



Synonym. — Trichonella spiralis. 



Distribution— Common in United States and many 

 European countries. Trichina was first discovered 

 by Peacock in 1828, in England. Found in about one 



